sorry, i missed the eCart 4 part of your title.
eCart 4 does not have the no gateway option.
Instead Select Paypal Payments Pro US as the payment gateway, then you can remove the code that processes the transaction through paypal.
After the pages have been created, remove the PayPal Express Checkout button from the Checkout page, and remove the local Checkout server behavior from the Confirm page.
You will also have to reset the redirect to the success page. double click the Universal Email server behavior and set the redirect to the success page.